guppies dying with no injuries or disease frequent water changes being made

Question
QUESTION: I have a 35 gallon hexagon tank, with probably to many livebearers to boot! I am not a novice at aquariums;I have nine different aquariums, however, this particular aquarium, the young guppies(not fry) are dropping dead right and left everyday!  I change the filter twice a week and do water changes of 20 to 30% at least two or three times a week because of the overcrowding.  I have tested all chemicals in the water; they are all o p.p.m, I have try parasite meds, melafix, maracyn, maracyn 2,salt, etc; and no not all at the same time; but over months and months; and to no avail, the guppies drop dead and a occasional platy!  I have no other place to put them because I have aqauriums with semi-aggressive species. Help!!!

ANSWER: Hi Suzanne
Can I ask? :)  How many guppies are in there?

What kind of test kit are you using-the dropper or the little strip kind?  

One thing I find kind of odd, all your readings are 0 ppm.  So I'm guessing you tested ammonia, nitrites, and nitrates then?  In a cycled tank, you should be showing 0 for the first two, and some nitrates.  If they're all 0, then your tank isn't cycled. Doing the frequent water changes helps that though.  Also, don't change out the filters that frequent, for one thing they're too expensive!  Buy a bag of filter floss-it's like white cotton, by the filter media section at the pet store.  It's about 4.00 a bag, just rip off a chunk and stuff it into the filter instead.

Using meds will stress the fish.  Also, just being in a crowded tank will stress the fish as well.  But, one thing I'm thinking of what may be happening, ph shock.  You're doing 2-3 water changes a week(which can also be stressful), which may alter the ph.  Then it will adjust during the days you don't change it, but then it's being altered again when you do the next water change.  With an overstocked tank on top of that, there's a lot of bioload being put out by those fish-and any organic stuff left in there will cause the ph to drop/crash.  Then, you do a water change, and it alters again....Have a ph test kit?  Try testing that a few times during the day/week and see if it fluctuates much.  Even slight fluctuations is enough to stress/kill a fish-especially if they're already in a stressed environment.

Let me know about those test kits too.

Christy



---------- FOLLOW-UP ----------

QUESTION: Christy, when I use the python water cleaner a lot of deitrus is being sucked out of the gravel; and I use a whisper filter with the bags or white pockets with charcoal in them; I don't want to have to change so often, but the filter is overflowing after just a few days, after I change the new filter.  I have tried to adjust the water flow in the aquarium; but that doesn't seem to help.  I was wondering I have had this aquarium for about two years and when I set it up; I used sea shells for decoration and they were sterilized by me before I placed them into the aquarium and were about five to ten years old before i put them in there also.  But I noticed that they are crumbling and I am concerened that that may be the problem; I have removed a lot of the fragments with the python, but I think I should remove them all together; do you agree?  I use a test kit that has droppers with a liquid medium that you put into the dropper with the aqaurium water sample to test.  You are right not all the measurements are o p.p.m, the nitrates are around 30; 0 ammonia, and I have a slight high p.h.; which I have always had because of the city water; and use salt to soften the water.  Thanks for your help, plus, I took out two dead fish guppies last night; and one so far today! Suzanne
ANSWER: Hi Suzanne
If the shells are crumbling, I'd probably go ahead and remove them.  Now shells can raise the ph in a tank.  How much depends on the shell and size of the tank.  I don't know how long they would "retain" their effectiveness to raise the ph-it's the calcium in them that causes it-I wonder if since they're crumbling, maybe it's altering the ph a bit by raising it?  If so, that may be enough to stress the fish and kill them.  

The dropper kits are better and more accurate, so that's good you have that.  Nitrates are ok, it used to be recommended under 40 ppm, now they're saying under 20 ppm, so I think you're still ok.  Especially with the frequent water changes.  How much salt are you adding to the water?  And, what kind of symptoms are the fish showing before they die, were you able to notice anything?

Do you have a mom and pop type of pet store around that will take some of the guppies for you?  Or, I'm guessing you have males and females together, can you get another small/medium sized tank to at least separate them?

Christy

---------- FOLLOW-UP ----------

QUESTION: I don't have another tank to seperate them at this time and now I don't know which offspring belongs to which original parents; the same goes with the platys! The fish have no signs of injuries to their skin or gills; and when I take them out they look perfectly health!  I have since taken out the sea shells and now I don't have any more dead fish; at least that I have found; and believe me I look hard for dead fish in this tank a few times a day.  There is a Mom and Pop store that will take them; but I love them like a dog; I know that sounds insane, but the babies are like my babies!

Answer
No, not insane, it's understandable.  But, if it's so overstocked that you have to change the water 2-3 times a week, and the filter pads twice a week, and still getting a lot of junk out of the gravel, it's beyond overstocked :) And it's just not healthy for the fish.  If they're not showing any outward signs, it's either some kind of internal bacterial, viral, or parasitic infection, or just stress.  Maybe work out something with the pet shop, become a breeder and give them the new fry after they're old enough.  Sorry....but you're going to continue having problems until you get the population under control by separating them, or giving some away.